In European waters, particularly the North Sea, the offshore wind power industry is developing rapidly and is seeking greater access to marine space to produce low carbon energy. The development of offshore wind farms is being encouraged by various financial incentives reflecting the European Union’s willingness to use renewable energy and to reduce its carbon emissions by 20% by 2020.

Today, an equivalent of 100 GW (gigawatts) of offshore wind power projects is planned, chiefly in the North Sea. It is expected that those projects will produce 373 TWh (terawatt hours) of electricity each year, corresponding to approximately 10% of the EU’s electricity demand, whilst avoiding 202 million tonnes of CO2 emissions every year. To reach a capacity of 100 GW, some 25,000 new turbines will have to be installed. With wind farms being spaced at around 1 km apart, this corresponds to a surface of 25,000km2 or 3% of the North Sea surface. This means that large-scale planning is required to avoid risks to sensitive areas and address the various activities taking place in the North Sea.

Costs and benefits

Growth in the offshore power generation business is set to be exponential in the coming decades. An important feature of most of the new installations will be their location further offshore and in deeper waters. Clearly, the development of offshore wind power facilities will cause additional human pressure on North Sea ecosystems. However there can also be benefits. Wind turbines and their foundations offer substrate to for marine species to grow on, they can function as artificial reefs and stimulate biodiversity locally. Also, since trawling is not possible within wind-farms, they can be regarded as de facto marine protected areas.

The challenge is to ensure that offshore wind projects are managed in a way that their impacts on marine ecosystems are minimized to acceptable levels and that those impacts are properly quantified. Recognizing the need to identify and manage the biodiversity risks and opportunities associated with offshore renewable energy, IUCN in collaboration with energy company E-ON and the Swedish International Development Cooperation Agency has carried out a comprehensive study and produced a guidance document Greening Blue Energy.